Simple fluorescence chemosensor for the detection of calcium ions in water samples and its application in bio-imaging of cancer cells.

This article describes the design, synthesis and characterization of a sensor suitable for practical measurement of ionized calcium in water samples and cancer cells. Calcium is an important ion in living organs and works as a messenger in several cellular functions. A lack of Ca ions interrupts the immune system and can lead to several diseases.

A ratiometric fluorescent sensor for detection of metformin based on terbium-1,10-phenanthroline-nitrogen-doped-graphene quantum dots.

Metformin (MTF), an effective biguanide and oral antihyperglycemic agent, is utilized to control blood glucose levels in patients with type II diabetes mellitus, and the determination of its concentration in biological fluids is one of the main issues in pharmacology and medicine. In this work, highly luminescent nitrogen-doped graphene quantum dots (N-GQDs) were modified using terbium (Tb)-1,10-phenanthroline (Phen) nanoparticles (NPs) to develop a dual-emission ratiometric fluorescent sensor for the determination of MTF in biological samples. The synthesized N-GQDs/Tb-Phen NPs were characterized using different techniques to confirm their physicochemical properties.

Concanavalin A-conjugated gold nanoparticle/silica quantum dot (AuNPs/SiQDs-Con A)-based platform as a fluorescent nanoprobe for the bioimaging of glycan-positive cancer cells.

The glycan receptor is a glycosylphosphatidylinositol glycoprotein that is overexpressed on the surface of various cancer cells and has been utilized for wide applications. In the present work, the surface of citrate-capped gold nanoparticles (cit-AuNPs) was modified with mercaptopropionic acid (MPA) molecules to provide carboxylic groups for secondary functionalization with amine anchored-silica quantum dots (Si-NH QDs) to produce cit-AuNPs-MPA/Si-NH QDs fluorescent nanoparticles. Concanavalin A (Con A) molecules were attached through thiol-AuNP bonds to produce the final cit-AuNPs/MPA/Si-NH QDs/Con A smart nanoparticles.